Open type ring furnaces are well known. British application GB 2,129,918 and U.S. Pat. Nos. 5,683,631 and 6,339,729 describe such ring furnaces.
Open type ring furnaces comprise series of baking pits that are delimited by hollow partitions, often called flue walls, and transverse walls. The partitions and walls are made of refractory bricks, such as those described in International Applications Nos. WO 95/22666 and WO 97/35150.
The baking pits are designed to receive green carbonaceous articles and packing material therein during the baking operations. The hollow partitions are intended for the circulation of heating flue and cooling gas during the baking operations. The transverse walls partition the furnace into a plurality of separate firing sections.
Groups of successive sections are simultaneously utilized to make up a baking sequence for a batch of carbonaceous articles. For that purpose, heating equipment is installed at a specific location of groups of sections while exhaust equipment is installed downstream of the heating means and blowing equipment is installed upstream of the same. After completion of a firing operation, all pieces of equipment are shifted downstream by a specified number of sections.
The applicants addressed the issue of finding ring furnaces that are more economical to make and operate than the known ring furnaces.